Geothermal Cooling - Low Energy Cooling for Sustainable Buildings - page 92

35

30

25

20

15

10

5

0

-5

-10

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Hours after 1 January 2002

Input air measured Output air measured Simulated - measured

Figure 4.6 Ambient air and outlet air of the earth heat exchanger in the moderate year of 2002. Also
shown is the temperature difference between the simulated and measured value

The cumulative frequency distribution of the exit air temperature shows that the
agreement between simulation and measurement is excellent at low exit temperatures,
that is in winter, and that in summer the simulated temperature is slightly lower than
the measured temperature (results from 2001 in Figure 4.8); 95% of all temperatures
are below 20 ◦ C, which shows the good summer cooling potential, and the temperature
is never below 0 ◦ C, which is excellent to prevent winter freezing of the heat recovery
unit in the mechanical ventilation system.

50.0

40.0

30.0

20.0

10.0

0.0

-10.0

-20.0

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Hours after 1 January 2003

Input air measured Output air measured Simulated - measured

Figure 4.7 Outlet temperatures of the earth heat exchanger in the warm year of 2003. Also shown is
the temperature difference between the simulated and measured value